Abusers, controlers can be very, very charming. Charm is part of the control. They are out to get what they want, so they put on the face to get just that. No man is going to say, Hi, my name is XXXX and I am an abuser (or a potential abuser). So the victim often no ho idea when she is getting into a relationship that she is seeing an abuser. After a time, after the "honeymoon" phase, eventually the abuse will start. In this case we have no idea when it started, if in Canada, in the US, after Bella's birth, or after Katie's but let me tell you, many many women stay in the relationship because of the abuser's lies, the confusion they elicit, because of financial reasons, and because of the children.
The abuser will tell his victim that no one else will want her, how pitiful she is, how she can't make it without him, how incompetent she is, that she is crazy. Then they go into the honeymoon phase, apologize, send flowers, pay attention to her, and so forth. Everything will be fine and rosy for a while, and then the cycle begins again. The abuse can start out to be just verbal, emotional, and either go no farther, or it can progress to physical abuse, even to death. Once a taboo such as slapping or hitting is broken, it is easier and easier for the abuser to move on to the next taboo, and break that one.
The victim could be a SAHM with no financial resources of her own, and feels she is unablke to support herself and her children, couldn't afford a divorce attorney. And the abuser will convince her that he has the resources and she will never get the children. But we do know that Nancy wanted to get a divorce from BC.